Continued from "Part I"
TECHNICAL
epidural injection in cats and dogs is almost always done through the lumbosacral space, however, large dogs can sometimes be exploited space sacro-coccygeal.
If it is true that, in dogs, the procedure may sometimes does not require general anesthesia, it becomes essential in the cat.
an important aspect sometimes overlooked in the course of epidural anesthesia is the prevention and treatment of hypotension produced by the blockade of the sympathetic system, which occurs after epidural injection of local anesthetics. Pets undergoing cesarean delivery appear to be particularly susceptible to this problem. It is recommended that the infusion of 20 ml / kg Ringer's lactate in both dogs and cats such as vascular support budget. In practice, this means a gain peripheral venous access and start as soon as the administration of fluids. The infusion may occur during site preparation and execution epidural injection.
positioning of the animal for the procedure may be the lateral decubitus position, both right and left, or sternal recumbency. In lateral decubitus position before the rear limbs are pulled in sternal recumbency they are brought under the animal and cranially. This placement ensures the best allocation between the last lumbar vertebra and the sacrum.
The landmarks for the correct location of the injection site are the wings of the ileum and the dorsal spinous processes of the last lumbar vertebra and the sacrum. Grade and, when possible, positioning sternum, which is easier to determine with precision the median sagittal line in which to insert the needle. The outer corners of the iliac wings should be palpated with the thumb and middle fingers, while the index is headed aboralmente. The crack is localized to the lumbosacral palpation, as a depression immediately caudal to the dorsal spinous process of the seventh lumbar vertebra. The needle cord is then inserted, slowly, with an angle of 90 degrees to the skin, taking care to put exactly on the median sagittal line. A button of local anesthetic can be performed in the conscious, even if an excess of anesthetic injected into tissues could distort the normal profile of the site, making more difficult the next step. The needle
choice is dictated by the size of the animal. A spinal needle 22 Gauge / 2.5 cm is applied in cats and small dogs, one of 20 Gauge / 3.8 cm in medium-sized dogs and a 18-Gauge / 7.5 cm in large dogs size.
by advancing the needle, when it encounters and beyond the ligament interarcuato, is more or less clearly discernible a sensation similar to needle passage through a thin plastic sheet. Should not you notice the passage of ligament and is met with resistance by bone, you just need to withdraw the needle and replace it with more appropriate direction.
The best way to ensure that the pin into the needle reaches the epidural space is actually the "test of strength loss." Injecting up to 2 ml of air or saline, the absence of resistance, confirming the correct location. Once the needle, you must ensure that there cerebrospinal fluid (CSF) or blood through it before starting the injection. The leakage of CSF indicates a subarachnoid puncture, in such cases, you can also inject, halving the calculated dose. In the case of bleeding from the needle is necessary to remove it and repeat the operation, since an accidental intravenous administration may result in signs of acute toxicity from local anesthetics, such as convulsions, cardiopulmonary depression, up to cardiac arrest and, of course , not to produce the desired local analgesia.
The anesthetic solution should be injected slowly, over a period of 30-60 seconds and must be at room temperature body.
